you say 'sorry i'm being a bit sheldon'
you start making physics jokes that your friends don't get
you need a flowchart to make friends
you start loving comic books and not knowing why
you start slagging off the other sciences
you, on your birthday, write 'hello shoroddy' on your hand and ask people if they get the joke
you have conversations about a photon is directed through a plane with two slits in it and either slit is observed it will not go through both slits. If it's unobserved, it will with your physics teacher without him bringing it up first.